Composite front windshield glass for high-speed vehicle and preparation method thereof

Abstract

The application relates to a composite front windshield glass for high-speed locomotives and a preparation method thereof, wherein the composite front windshield glass for high-speed locomotives comprises a splash-proof layer, an electric heating assembly, a plurality of super-strong chemical glass layers and a bonding layer, at least one of the bonding layers is a PVB / high-modulus K2O.nSiO2-based nano-soft fiber / PVB interpenetrating network film. The application overcomes the defects that the PVB film for high-speed locomotives in the prior art cannot be flame-retardant in a sudden fire, and avoids the shortcomings that the PVB adhesive layer is flammable, easy to bubble and poor in impact strength.

Description

Technical Field

[0001] This invention relates to the field of glass, specifically to composite windshield glass for high-speed trains with speeds of 350 km / h or higher and its preparation method. Background Technology

[0002] In the sea, land, and air transportation system comprised of airplanes, trains, automobiles, and ships, railway transportation boasts advantages such as large capacity, high speed, long distance, low cost, and low pollution. It has gradually gained the upper hand in competition with other modes of transportation, becoming the most important system. High-speed rail can transport large quantities of goods and people to distant locations in a shorter time, driving rapid economic development along the railway lines, in regions, and even nationwide, thus becoming a leader in the railway system. By early 2024, 25 countries worldwide had passenger trains with maximum operating speeds exceeding 240 km / h, and these countries also possessed world-leading high-speed train windshield technology. When my country's high-speed trains operated at lower speeds than those abroad, importing windshields was a viable alternative, and these problems were not significant. However, as my country's high-speed rail speeds have gradually increased and far exceeded those of other countries, there are no readily available fire-resistant and heat-insulating high-speed train windshields available for our use. Imports cannot solve the problem, and the issue of windshields has become increasingly prominent. Furthermore, after my country's high-speed trains reached a world-leading level, it has transformed from an importer to an exporter, making the fire safety of windshields a crucial issue that must be addressed.

[0003] Currently, the windshields used in most domestic trains are made of ordinary safety glass, which cannot meet the fire safety requirements of high-speed locomotives, especially the safety requirements of high-speed locomotives with speeds exceeding 350 km / h.

[0004] High-speed locomotive windshields are generally used outdoors. Since existing PVB films are flammable materials, they pose fire safety hazards and, in severe cases, threaten the operational safety of the locomotive and affect the service life of the windshield. Summary of the Invention

[0005] The main objective of this invention is to provide a composite windshield glass for high-speed locomotives and its preparation method, which overcomes the shortcomings of existing PVB films for high-speed locomotives that cannot be flame-retardant in the event of a sudden fire, and avoids the disadvantages of PVB adhesive layers such as flammability, bubbling, and poor impact resistance.

[0006] The objective of this invention and the technical problem it solves are achieved by the following technical solutions.

[0007] A composite windshield for high-speed locomotives includes a splash-proof layer, an electrothermal component, several layers of ultra-strong chemical tempered glass, and an adhesive layer. The adhesive layers are located between the ultra-strong chemical tempered glass layers. At least one adhesive layer is made of a PVB / high-modulus K₂O·nSiO₂-based nanofiber / PVB interpenetrating network film. The PVB / high-modulus K₂O·nSiO₂-based nanofiber / PVB interpenetrating network film is manufactured through the following steps:

[0008] Step 1) At room temperature, the K2O·nSiO2-based pre-reactive spinning solution is injected into a multi-channel in-situ electrospinning device. A stainless steel needle with a diameter of 0.8 mm is used as a metal nozzle, and a grounded stainless steel cylinder covered with aluminum foil is used as a collector. The distance between the nozzle and the collector is 15 cm. The electrospinning voltage is set to 20 kV, and the pre-reactive spinning solution is spun into the collector at a rate of 0.6 ml / h per channel, forming a low-modulus K2O·nSiO2-based nanofiber network in the form of a nonwoven fabric on its surface. The fiber diameter is 200-600 nm. By controlling the spinning time, low-modulus K2O·nSiO2-based nanofiber membranes of different thicknesses can be obtained.

[0009] Step 2) Peel the K2O·nSiO2-based nanofiber membrane from the aluminum foil and place it evenly between two 0.38mm PVB films. Then place a 0.1mm polyimide (PI) film on each side of the PVB / low-modulus K2O·nSiO2-based nanofiber membrane / PVB composite to ensure the isolation between PVB and glass.

[0010] Step 3) The laminated assembly of 5mm tempered glass / PI / PVB / low-modulus K2O·nSiO2-based nanofiber film / PVB / PI / 5mm tempered glass is placed in a continuous roller press for hot pressing. After the first roller pressing heat treatment (pressure 0.3±0.1MPa, temperature 40±5℃, roller spacing 88%~92% of the laminated assembly thickness), it undergoes a second roller pressing heat treatment (pressure 0.5±0.1MPa, temperature 70±5℃, roller spacing 88%~92% of the laminated assembly thickness) to finally obtain a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film.

[0011] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0012] Preferably, the K2O·nSi iO2-based pre-reactive spinning solution is prepared from silica sol obtained by acid hydrolysis of tetraethyl orthosilicate. The silica sol consists of unimodal, narrowly distributed nanoparticles with a core-shell structure. The core layer is composed of nano-silica sol and its aggregates, while the shell layer is polyvinyl alcohol. The surface tension of this spinning solution is controlled within the range of 17.50 ± 2.50 mN / m, and the modulus is controlled between 4.0 and 4.5. The modulus is K2O·nSi The value of n in iO2; the K2O·nSiO2-based pre-reactive spinning solution is composed of the following substances: 18-75 parts of tetraethyl orthosilicate, 0.1-0.5 parts of nitric acid, 30-120 parts of deionized water, 50-200 parts of polyethanol aqueous solution (solid content: 5wt%; molecular weight: 80000-100000; degree of hydrolysis: 85%-90%), 2-4 parts of ethanol, 1-2 parts of reactive emulsifier SE-10N, 0.4-1.2 parts of ammonia (20wt%), and 4-8 parts of potassium hydroxide (purity 85wt%).

[0013] Preferably, the aforementioned K2O·nSiO2-based pre-reactive spinning solution is composed of the following raw materials in parts by weight: 25-55 parts of tetraethyl orthosilicate, 0.2-0.4 parts of nitric acid, 45-70 parts of deionized water, 75-133 parts of polyethanol aqueous solution (solid content: 5wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 2.5-3.5 parts of ethanol, 1.3-1.7 parts of reactive emulsifier SE-10N, 0.6-1.0 parts of ammonia (20wt%), and 4.5-6.5 parts of potassium hydroxide (purity 85wt%).

[0014] The optimized K2O·nSiO2-based pre-reactive spinning solution, wherein the nano-silica sol has a particle size of 70nm to 100nm, the core layer of the core-shell structured silica sol has a particle size of 50nm to 70nm, the shell layer thickness is 10nm to 15nm, and the viscosity is 80 to 150mPa·s.

[0015] The objectives of this invention and the technical problems it solves are also achieved by the following technical solutions.

[0016] According to the present invention, a composite windshield for high-speed locomotives and its manufacturing method thereof are provided, comprising:

[0017] Tetraethyl orthosilicate, nitric acid, and deionized water are mixed in a weight ratio of 18–75: 0.1–0.5: 30–120. The mixture is stirred at room temperature for at least 60 minutes to allow it to fully hydrolyze. After it forms a single-peaked, narrowly distributed silica sol with a particle size of 40 nm–80 nm, it is stirred for another 60 minutes to obtain the first mixed solution.

[0018] A first mixed solution is prepared by mixing polyvinyl alcohol aqueous solution (solid content: 5wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), ethanol, and reactive emulsifier SE-10N in a weight ratio of 50-200:2-4:1-2. The mixture is stirred at room temperature for at least 60 minutes to allow polyvinyl alcohol to uniformly coat the surface of silica sol, thereby obtaining a second mixed solution with a viscosity maintained in the range of 20-80 mPa·s.

[0019] Slowly add 0.4 to 1.2 parts of ammonia water (20 wt%) to the second mixed solution, and stir for at least 60 minutes at room temperature to obtain the third mixed solution, ensuring that its pH value is maintained between 6 and 7;

[0020] Add 4 to 8 parts of potassium hydroxide (85 wt% purity) stepwise to the third mixed solution, ensuring that the temperature of the solution system is below 25°C. After vacuum defoaming for 60 minutes, a K2O·nSiO2-based pre-reactive spinning solution is obtained, with its viscosity maintained in the range of 40 to 210 mPa·s.

[0021] At room temperature, a K2O·nSiO2-based pre-reactive spinning solution was injected into a multi-channel in-situ electrospinning device. A 0.8mm diameter stainless steel needle was used as the metal nozzle, and a grounded stainless steel cylinder covered with aluminum foil served as the collector. The distance between the nozzle and the collector was 15cm. The electrospinning voltage was set to 20kV, and the pre-reactive spinning solution was spun into the collector at a rate of 0.6ml / h per channel, forming a non-woven K2O·nSiO2-based nanofiber network on its surface. The fiber diameter ranged from 200 to 600nm. By controlling the spinning time, low-modulus K2O·nSiO2-based nanofiber membranes of different thicknesses could be obtained.

[0022] The low-modulus K2O·nSiO2-based nanofiber membrane was peeled off from the aluminum foil and evenly placed between two 0.38mm PVB films. Then, a 0.1mm polyimide (PI) film was placed on each side of the PVB / low-modulus K2O·nSiO2-based nanofiber membrane / PVB composite to ensure the isolation between PVB and glass.

[0023] A composite material consisting of 5mm tempered glass, PI, PVB, low-modulus K2O·nSiO2-based nanofiber film, PVB, PI, and 5mm tempered glass is placed in a continuous roll press for hot pressing. After a first roll pressing heat treatment (pressure 0.3±0.1MPa, temperature 40±5℃, roll spacing 88%–92% of the thickness of the pressed composite), it undergoes a second roll pressing heat treatment (pressure 0.5±0.1MPa, roll temperature 70±5℃, roll spacing 88%–92% of the thickness of the pressed composite after the first pressing) to finally obtain a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film.

[0024] The quantity and layout of the heating wire, input busbar, output busbar, input wire, and output wire are designed according to the heating requirements. The heating wire, input busbar, output busbar, input wire, and output wire are arranged on the first layer of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. The input wire and the output wire protrude out of the first layer of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film to obtain the first layer of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. The first layer of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is prepared by roll pressing. Among them, the first layer of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film that is first in position from the outside to the inside. "From the outside to the inside" refers to the positional relationship of each part of the composite windshield glass for high-speed locomotives relative to the inside and outside of the carriage when it is installed on a high-speed locomotive.

[0025] First, a first layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film is laid on the ultra-strong chemically tempered glass, allowing the input and output wires to protrude from the windshield. A second layer of ultra-strong chemically tempered glass is then laid on top of the first layer, followed by several layers of uniformly thick second layers of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film. A third layer of ultra-strong chemically tempered glass is then laid on top of the second layer, and so on. Finally, the third layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film is passed through the third layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film. An anti-splash layer is laid on top of an iO2-based nanofiber / PVB interpenetrating network film. Finally, the stacked ultra-strong chemically tempered glass layer, PVB / high-modulus K2O·nS iO2-based nanofiber / PVB interpenetrating network film, and anti-splash layer are placed together in a vacuum bag and evacuated. The vacuum bag is then placed in an autoclave and reacted at 110–115°C and 1–1.5 MPa for 0.5–1.5 hours. The vacuum bag is then removed to obtain a composite windshield for high-speed locomotives.

[0026] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0027] Preferably, in the aforementioned composite windshield for high-speed locomotives, the thickness of the polyvinyl butyral (PVB) film is 0.3 to 1.2 mm.

[0028] Preferably, in the aforementioned composite windshield for high-speed locomotives, the surface stress of the ultra-strong chemically tempered glass is 500MPa to 700MPa, the stress layer depth is 30 to 40μm, and the thickness is 4 to 8mm.

[0029] By employing the above technical solution, the composite windshield for high-speed locomotives provided by the present invention has at least the following advantages:

[0030] 1. K₂O·nSiO₂, as an inorganic solid material, is brittle and cannot be directly extruded, injection molded, compressed, or stretched into filaments. Furthermore, as an inorganic salt, K₂O·nSiO₂ is highly water-soluble and cannot be prepared into a colloidal solution. This invention utilizes the sol-gel method to synthesize a core-shell structured SiO₂ sol with the aid of polyvinyl alcohol and an emulsifier. By leveraging the steric hindrance effect of polyvinyl alcohol, the reaction between silicon dioxide and potassium hydroxide is delayed at room temperature (25°C) to obtain a K₂O·nSiO₂-based pre-reacting spinning solution. Then, using multi-channel in-situ electrospinning technology, K₂O·nSiO₂-based nanofiber membranes of varying thicknesses are prepared.

[0031] 2. Due to the poor compatibility between PVB film and K2O·nSiO2 material, it is impossible to directly prepare composite films with a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB structure. This invention utilizes a roll pressing process to press incompletely reacted low-modulus K2O·nSiO2-based nanofibers into PVB film, forming a PVB / low-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network layer. Further hot pressing generates a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network layer, improving the penetration ability of K2O·nSiO2-based fibers in the PVB film. The interpenetrating network structure also increases the bonding force between PVB and K2O·nSiO2, creating a reinforcement effect similar to reinforced concrete.

[0032] 3. The reason why the PVB / high-modulus K2O·nSiO2-based nanofiber / PVB film of this invention has flame retardancy and flame spread isolation is that: the K2O·nSiO2-based material that forms an interpenetrating network structure with the PVB film will quickly foam upon contact with an open flame, forming a heat insulation layer that prevents the flame from continuing to penetrate the film, thereby ensuring the integrity of the windshield of the high-speed locomotive; the first layer of PVB film in the PVB / high-modulus K2O·nSiO2-based nanofiber / PVB film also acts as a charring agent, which can carbonize at high temperatures to form long-chain carbides and absorb a large amount of heat; while the second layer of PVB film in the PVB / high-modulus K2O·nSiO2-based nanofiber / PVB film will not come into direct contact with an open flame due to the presence of the K2O·nSiO2-based foamed heat insulation layer. Over time, this layer of film will only slowly heat up and will not ignite, thereby improving the fire safety performance of the locomotive windshield.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a composite windshield for high-speed locomotives according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the electrothermal assembly and adhesive layer structure of a composite windshield for high-speed locomotives provided in one embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the operation of a composite windshield electric heating system for high-speed locomotives provided in one embodiment of the present invention;

[0037] Figure 4This is a schematic diagram of the electrothermal assembly and adhesive layer structure of a composite windshield for high-speed locomotives provided in another embodiment of the present invention.

[0038] In the diagram, 1-Antireflective coating layer; 2-First layer of ultra-strong chemically tempered glass; 3-First layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film; 3-1-PVB layer; 3-2-PVB / high-modulus K2O·nSiO2-based nanofiber interpenetrating network structure layer; 3-3-High-modulus K2O·nSiO2-based nanofiber layer; 4-Second layer of ultra-strong chemically tempered glass; 5-Second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film; 6-Third layer of ultra-strong chemical glass; 7-Anti-splash layer; 8-Heating component; 81-Heating wire; 821-Input busbar; 822-Output busbar; 831-Input wire; 832-Output wire. Detailed Implementation

[0039] The composite windshield for high-speed locomotives of this invention includes an anti-splash layer, an electrothermal component, several ultra-strong chemical glass layers, and an adhesive layer. At least one of the adhesive layers is a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. The PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is prepared by the following steps. By weight, the high-modulus K2O·nSiO2-based nanofiber is composed of the following substances:

[0040] 18-75 parts of tetraethyl orthosilicate, 0.1-0.5 parts of nitric acid, 30-120 parts of deionized water, 50-200 parts of polyethanol aqueous solution (solid content: 5wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 2-4 parts of ethanol, 1-2 parts of reactive emulsifier SE-10N, 0.4-1.2 parts of ammonia (20wt%), and 4-8 parts of potassium hydroxide (purity 85wt%). The high-modulus K2O·nSiO2-based nanofibers are prepared from K2O·nSiO2-based pre-reaction spinning solution. The K2O·nSiO2-based pre-reaction spinning solution is prepared from silica sol obtained by acid hydrolysis of tetraethyl orthosilicate. The silica sol consists of nanoparticles with a single-peak narrow distribution and a core-shell structure. The core material is nano-silica sol and its aggregates, and the shell material is polyvinyl alcohol. The surface tension of the spinning solution is controlled within the range of 17.50±2.50 mN / m, and the modulus is controlled between 4.0 and 4.5.

[0041] As a preferred embodiment, the K2O·nSiO2-based pre-reactive spinning solution, by weight, comprises the following raw materials: 25-55 parts of tetraethyl orthosilicate, 0.2-0.4 parts of nitric acid, 45-70 parts of deionized water, 75-133 parts of polyethanol aqueous solution (solid content: 5wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 2.5-3.5 parts of ethanol, 1.3-1.7 parts of reactive emulsifier SE-10N, 0.6-1.0 parts of ammonia (20wt%), and 4.5-6.5 parts of potassium hydroxide (purity 85wt%).

[0042] In a preferred embodiment, the core-shell structured nano-silica sol has a particle size of 70nm to 100nm, a narrow single-peak particle size distribution, a core layer particle size of 50nm to 70nm, a shell layer thickness of 10nm to 15nm, and a viscosity of 80 to 150mPa·s.

[0043] This invention uses a core-shell structured silica sol as the main raw material for high-modulus K₂O·nSiO₂-based soft nanofibers. The particle size of this core-shell silica sol is 70 nm to 100 nm, and the core layer particle size is 50 nm to 70 nm. The shell material is polyvinyl alcohol, and the shell thickness is 10 nm to 15 nm. This invention features low viscosity and a low reaction rate at room temperature (25°C), enabling the preparation of soft nanofibers with controllable diameter. Furthermore, it can be used at low temperatures down to -55°C ± 1°C and withstands ultraviolet radiation for over 4000 hours.

[0044] The reason why this PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film has the properties of low temperature resistance and UV radiation resistance is:

[0045] 1. High-modulus K2O·nSiO2-based nanofibers have high solid content and very low free water content;

[0046] 2. The sealing performance of PVB film can firmly encapsulate the high-modulus K2O·nSiO2-based nanofibers, preventing the loss of free water and bound water in K2O·nSiO2, and ensuring that the transmittance of PVB / high-modulus K2O·nSiO2-based nanofibers / PVB interpenetrating network film will not gradually decrease under long-term ultraviolet radiation.

[0047] 3. The density of the PVB film and the presence of the K2O·nSiO2-based fiber / PVB interpenetrating network ensure that the remaining trace amounts of free water will not form large-sized, continuous ice crystal phases in low-temperature environments, thus ensuring the transparency of the locomotive glass under extremely cold conditions.

[0048] The nano-silica sol used in this embodiment of the invention has a core-shell structure, which enriches different components on the inner or outer side of the particles, i.e., core-shell particles, thereby giving the core and shell different functions and obtaining particles with excellent performance; wherein the core material is nano-silica sol and the shell material is polyvinyl alcohol. During low-temperature storage, the shell material encapsulates the core material, silica sol, and isolates the silica from potassium hydroxide, preventing a reversal reaction. When the temperature is higher, above the glass transition temperature of the shell polymer, the shell polymer changes from a glassy state to a rubbery state. The potassium hydroxide solution penetrates into the shell and reacts with the silica sol to form potassium silicate solution, i.e., potassium silicate (its structural formula is K2O·nSiO2, where n is the modulus). The silica network skeleton formed after the potassium silicate hardens has very little decrease in hardness at high temperatures, exhibits good flame retardancy, and is heat-resistant and fireproof, enhancing the heat resistance of PVB / high-modulus K2O·nSiO2-based nanofiber membrane / PVB interpenetrating network film.

[0049] The PVB / low-modulus K2O·nSiO2-based nanofiber membrane / PVB film with interpenetrating network structure in this invention is prepared by the following steps:

[0050] (1) Mix tetraethyl orthosilicate, nitric acid and deionized water in a weight ratio of 18-75: 0.1-0.5: 30-120, stir at room temperature for at least 60 minutes to allow the mixture to fully hydrolyze, and stir for another 60 minutes after it forms a single-peak, narrow-distribution silica sol with a particle size of 40nm-80nm to obtain the first mixed solution.

[0051] (2) Add the polyvinyl alcohol aqueous solution (solid content: 5wt%; molecular weight: 80000~100000; degree of hydrolysis: 85%~90%), ethanol, and reactive emulsifier SE-10N to the first mixed solution in a weight ratio of 50~200:2~4:1~2. Stir at room temperature for at least 60 minutes to allow the polyvinyl alcohol to be uniformly coated on the surface of silica sol to obtain the second mixed solution, the viscosity of which is maintained in the range of 20~80mPa·s.

[0052] (3) Slowly add 0.4 to 1.2 parts of ammonia water (20 wt%) to the second mixed solution and stir for at least 60 minutes at room temperature to obtain the third mixed solution, ensuring that its pH value is maintained between 6 and 7;

[0053] (4) Add 4 to 8 parts of potassium hydroxide (purity 85wt%) to the third mixed solution in steps, ensuring that the temperature of the solution system is below 25℃. After vacuum defoaming for 60 minutes, K2O·nSiO2-based pre-reaction spinning solution is obtained, and its viscosity is maintained in the range of 40 to 210 mPa·s.

[0054] (5) Under room temperature conditions, the K2O·nSiO2-based pre-reaction spinning solution was injected into a multi-channel in-situ electrospinning device. A stainless steel needle with a diameter of 0.8 mm was used as a metal nozzle, and a grounded stainless steel cylinder covered with aluminum foil was used as a collector. The distance between the nozzle and the collector was 15 cm. The electrospinning voltage was set to 20 kV, and the pre-reaction spinning solution was spun into the collector at a rate of 0.6 ml / h per channel. A non-woven K2O·nSiO2-based nanofiber network was formed on its surface. The fiber diameter was 200-600 nm. By controlling the spinning time, low-modulus K2O·nSiO2-based nanofiber membranes of different thicknesses could be obtained.

[0055] (6) Peel the low-modulus K2O·nSiO2-based nanofiber membrane from the aluminum foil and place it evenly between two 0.38mm PVB films. Then place a 0.1mm polyimide (PI) film on each side of the PVB / low-modulus K2O·nSiO2-based nanofiber membrane / PVB composite to ensure the isolation between PVB and glass.

[0056] (7) The assembly of 5mm tempered glass / PI / PVB / low modulus K2O·nSiO2-based nanofiber film / PVB / PI / 5mm tempered glass is placed in a continuous roll press for hot pressing. After the first roll pressing heat treatment (pressure 0.3±0.1MPa, temperature 40±5℃, roll gap 88%~92% of the thickness of the pressed assembly), it is subjected to a second roll pressing heat treatment (roll pressing 0.5±0.1MPa, roll temperature 70±5℃, roll gap 88%~92% of the thickness of the pressed assembly after the first pressing) to finally obtain PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film.

[0057] (8) Design the quantity and layout of heating wire, input busbar, output busbar, input wire and output wire according to heating requirements. Arrange heating wire, input busbar, output busbar, input wire and output wire on the first layer of PVB film of the first layer of PVB / high modulus K2O·nSiO2-based nano-soft fiber / PVB interpenetrating network film. Make the input wire and the output wire protrude out of the first layer of PVB film of the first layer of PVB / high modulus K2O·nSiO2-based nano-soft fiber / PVB interpenetrating network film. Use the roll pressing method to press the heating wire, input busbar, output busbar, input wire and output wire together with the first layer of PVB / high modulus K2O·nSiO2-based nano-soft fiber / PVB interpenetrating network film.

[0058] (9) A first layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film is laid on the ultra-strong chemically tempered glass, so that the input wire and the output wire protrude from the windshield. A second layer of ultra-strong chemically tempered glass is laid on the first layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film, and then several layers of uniformly thick second layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film are laid. Then a third layer of ultra-strong chemically tempered glass is laid on the second layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film, and then the third layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film is laid. An anti-splash layer is laid on top of an iO2-based nanofiber / PVB interpenetrating network film. Finally, the stacked ultra-strong chemically tempered glass layer, PVB / high-modulus K2O·nS iO2-based nanofiber / PVB interpenetrating network film, and anti-splash layer are placed together in a vacuum bag and evacuated. The vacuum bag is then placed in an autoclave and reacted at 110–115°C and 1–1.5 MPa for 0.5–1.5 hours. The vacuum bag is then removed to obtain a composite windshield for high-speed locomotives.

[0059] In the preparation of the composite windshield glass for high-speed locomotives according to the embodiments of the present invention, tetraethyl orthosilicate, nitric acid, and deionized water are stirred and hydrolyzed at room temperature to obtain a first mixed solution; polyvinyl alcohol, ethanol, and SE-10N are added to the first mixed solution to obtain a second mixed solution; ammonia is added to the second mixed solution to obtain a third mixed solution; potassium hydroxide with a purity of 85 wt% is added to the third mixed solution to obtain a K2O·nSiO2-based pre-reaction spinning solution; a low-modulus K2O·nSiO2-based nanofiber membrane is obtained using a multi-channel in-situ electrospinning device; a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is obtained using a rolling process; a first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film with attached electrothermal components is obtained using a rotary spinning device; and a high-pressure lamination process is used to obtain the composite windshield glass for high-speed locomotives.

[0060] The composite windshield for high-speed locomotives provided in this invention, when exposed to fire, rapidly foams and expands the high-modulus K2O·nSiO2-based nanofibers in the windshield to form a heat-insulating, fire-resistant foam layer, absorbing a large amount of heat generated by the fire and exhibiting excellent fire resistance. The fire-resistant adhesive layer of the windshield is formed using the aforementioned fiber material, giving the windshield advantages such as being free of microbubbles, having high transmittance, and providing long-lasting fire resistance. Preferably, there are at least two interlayers, one of which is a hollow layer, and the remaining interlayers are fire-resistant adhesive layers.

[0061] In a preferred embodiment, the thickness of the high-modulus K2O·nSiO2-based nanofiber layer is 0.1-0.5 mm.

[0062] This invention can control the thickness of high-modulus K2O·nSiO2-based nanofibers to 0.1-0.5mm, ensuring the fire resistance of the locomotive windshield while maintaining a relatively stable thickness, thus reducing production costs and expanding the application range of the glass. In this embodiment of the invention, the fire-resistant adhesive layer in the windshield expands upon exposure to fire, forming a porous heat-insulating layer. The thickness of this expanded layer is approximately 20 to 50 times that of the original fiber layer. Upon exposure to fire, the glass on the fire-facing side will shatter first, and then the fire-resistant adhesive layer attached to it will gradually form a heat-insulating layer of approximately 2mm to 20mm. If the fiber layer thickness is less than 0.1mm, it is too thin to form a continuous heat-insulating layer, allowing open flames to pass directly through and ignite the PVB film behind the fiber layer. This fails to isolate heat transfer for a certain period, resulting in an overall fire resistance time lower than the design value. If the fiber layer thickness is greater than 0.5mm, it is too thick, leading to excessively high windshield costs. An excessively thick expanded layer can cause the entire glass to detach, thus reducing fire resistance.

[0063] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0064] All reagents used in the embodiments of this invention are commercially available products.

[0065] Example 1

[0066] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0067] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0068] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%), and 5.2 kg potassium hydroxide (purity 85 wt%). Since the particle size distribution of the nano-core-shell structured silica sol is narrow, sol particles of various sizes can exist in this invention, exhibiting a unimodal state. Similarly, the particle size distribution of the sol particles in the following examples is also narrow.

[0069] (2) Prepare K2O·nSiO2-based pre-reaction spinning solution from the above raw materials according to the following steps:

[0070] Mix 37.12 kg of tetraethyl orthosilicate, 0.3 kg of nitric acid, and 57.73 kg of deionized water, and stir at room temperature for at least 60 minutes to allow the mixture to fully hydrolyze. After forming a silica sol with a particle size of 50 nm to 70 nm, stir for another 60 minutes to obtain the first mixed solution.

[0071] 100 kg of polyvinyl alcohol aqueous solution (solid content: 5 wt%; molecular weight: 80,000–100,000; degree of hydrolysis: 85%–90%), 3 kg of ethanol, and 1.5 kg of reactive emulsifier SE-10N were mixed and added to the first mixed solution. The mixture was stirred at room temperature for at least 60 minutes to allow the polyvinyl alcohol to be uniformly coated on the surface of the silica sol, thus obtaining the second mixed solution with a viscosity maintained in the range of 20–80 mPa·s.

[0072] 0.8 kg of ammonia water (20 wt%) was slowly added to the second mixed solution, and stirred at room temperature for at least 60 minutes to obtain the third mixed solution, ensuring that its pH value was maintained between 6 and 7.

[0073] 5.2 kg of potassium hydroxide (85 wt% purity) was added to the third mixed solution in steps, ensuring that the temperature of the solution system was below 25 °C. After vacuum defoaming for 60 minutes, a K2O·nSiO2-based pre-reaction spinning solution was obtained, with its viscosity maintained in the range of 40–210 mPa·s.

[0074] The PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is prepared using the above-mentioned K2O·nSiO2-based pre-reactive spinning solution through the following steps:

[0075] At room temperature, a K2O·nSiO2-based pre-reactive spinning solution was injected into a multi-channel in-situ electrospinning device. A 0.8mm diameter stainless steel needle was used as the metal nozzle, and a grounded stainless steel cylinder covered with aluminum foil served as the collector. The distance between the nozzle and the collector was 15cm. The electrospinning voltage was set to 20kV, and the pre-reactive spinning solution was spun into the collector at a rate of 0.6ml / h per channel, forming a non-woven K2O·nSiO2-based nanofiber network on its surface. The fiber diameter ranged from 200 to 600nm. By controlling the spinning time, low-modulus K2O·nSiO2-based nanofiber membranes of different thicknesses could be obtained.

[0076] The low-modulus K2O·nSiO2-based nanofiber membrane was peeled off from the aluminum foil and evenly placed between two 0.38mm PVB films. Then, a 0.1mm polyimide (PI) film was placed on each side of the PVB / low-modulus K2O·nSiO2-based nanofiber membrane / PVB composite to ensure the isolation between PVB and glass.

[0077] A composite material consisting of 5mm tempered glass, PI, PVB, low-modulus K2O·nSiO2-based nanofiber film, PVB, PI, and 5mm tempered glass is placed in a continuous roll press for hot pressing. After a first heat treatment (pressure 0.3±0.1MPa, temperature 40±5℃, roll spacing equal to 88%–92% of the thickness of the pressed composite), it undergoes a second heat treatment (pressure 0.5±0.1MPa, temperature 70±5℃, roll spacing equal to 88%–92% of the thickness of the pressed composite after the first heat treatment), ultimately yielding a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film.

[0078] In this embodiment, the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached heating element is prepared by the following steps using the aforementioned PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached heating element:

[0079] See Figure 2The electric heating component 8 includes several heating wires 81, an input busbar 821, an output busbar 822, an input wire 831, and an output wire 832. The number of heating wires 81 is determined according to the specific heating power requirements. The heating wires 81 are distributed according to the heating power requirements and are arranged in the first layer of PVB / high-modulus K2O·nSi iO2-based nanofiber / PVB interpenetrating network film 3. To ensure uniform heating of the first layer of ultra-strong chemically tempered glass 2 (coated with an anti-reflective layer 1), it is preferable that the heating wires 81 are evenly distributed in the first layer of PVB / high-modulus K2O·nSi iO2. In the iO2-based nanofiber / PVB interpenetrating network film 3, busbars (including input busbar 821 and output busbar 822) are used to connect the ends of the heating wires 81 at the same end, so that several heating wires 81 are connected in parallel. The output end of the input busbar 821 is connected to the input end of the several heating wires, and the input end of the output busbar 822 is connected to the output end of the several heating wires. The output end of the input wire 831 is connected to the input end of the input busbar 821, and the input end of the input wire 831 extends out of the first layer of ultra-strong chemical tempered glass 2, the second layer of ultra-strong chemical tempered glass 4, and the first layer of PVB / high modulus K2O·nSi. O2-based nanofiber / PVB interpenetrating network film 3 is used to connect to the output terminal of an external power source; the input terminal of the output conductor 832 is connected to the output terminal of the output busbar 822, and the output terminal of the output conductor 832 extends out through the first layer of ultra-strong chemical tempered glass 2, the second layer of ultra-strong chemical tempered glass 4, and the first layer of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film 3, which is used to connect to the input terminal of the external power source.

[0080] See Figure 3 When encountering icy, snowy, or freezing rain weather, the input wire 831 of the composite windshield for high-speed locomotives is connected to the output terminal of an external power source, and its output wire 832 is connected to the input terminal of the external power source. This creates a closed loop between the heating element 8 of the composite windshield for high-speed locomotives and the external power source. The current supplied by the external power source flows into the input wire 831 through its output terminal, and then into the input terminal of the input busbar 821. The current is then distributed through the input busbar 821 to the parallel heating wire 81, which generates heat to melt the ice and snow covering the first layer of ultra-strong chemically tempered glass 2 with the anti-reflective layer 1. The current flowing through the heating wire 81 is collected at the output busbar 822 and returns to the input terminal of the external power source via the output wire 832.

[0081] The composite windshield for high-speed locomotives provided in this invention utilizes an electric heating wire embedded within a PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. This heating wire is connected to an external power source via a wire, enabling electric heating of the composite windshield without affecting its normal light transmission. This effectively removes snow or frost from the outer surface of the windshield, preventing low light transmittance and impaired driver visibility caused by snow or frost accumulation, which can even threaten locomotive safety in severe cases. This extends the service life of the composite windshield for high-speed locomotives.

[0082] The composite windshield for high-speed locomotives has an input wire 831 connected to the output terminal of a temperature controller, and an output wire 832 connected to the input terminal of the temperature controller. The composite windshield is controlled to open or close by the temperature controller. When the train is running at high speed and encounters severe weather such as rain or snow, it is necessary to promptly clear snow and frost from the windshield surface. In this embodiment, the heating component is connected to the temperature controller, which can preset temperature parameters to control the heating of the electric heating component, achieving automatic de-icing at low temperatures, which is particularly suitable for harsh environments in northern regions.

[0083] The composite windshield for high-speed locomotives in this embodiment is a composite windshield for high-speed locomotives prepared by the above-mentioned PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film through the following steps:

[0084] (1) Prepare 3 pieces of 5mm thick ultra-strong chemically tempered glass;

[0085] (2) See Figure 1A first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film (301: PVB film, 302: transition layer, 303: high-modulus K2O·nSiO2-based nanofiber) is laid on the first layer of ultra-strong chemically tempered glass 2, so that the input wire 831 and the output wire 832 protrude from the composite windshield of the high-speed locomotive. A second layer of ultra-strong chemically tempered glass 4 is laid on the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film 3, and then several layers of uniformly thick second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film 5 are laid. Then, the second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film 5 is laid on the second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film 5 is laid on the first layer of ultra-strong chemically tempered glass 2. A third layer of ultra-strong chemically tempered glass 6 is laid on the iO2-based nanofiber / PVB interpenetrating network film 5, and then an anti-splash layer 7 is laid on top through a third adhesive layer (containing only PVB film). Finally, the stacked ultra-strong chemically tempered glass, PVB / high modulus K2O·nS iO2-based nanofiber / PVB interpenetrating network film and anti-splash layer 7 are placed together in a vacuum bag and vacuumed. The vacuum bag is then placed in an autoclave and reacted at 110-115℃ and 1-1.5 MPa for 0.5-1.5 hours. The vacuum bag is then removed to obtain a composite windshield glass for high-speed locomotives.

[0086] Example 2

[0087] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0088] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0089] 37.12 kg tetraethyl orthosilicate, 0.2 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.5 kg ammonia (20 wt%), and 5.2 kg potassium hydroxide (purity 85 wt%);

[0090] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0091] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0092] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0093] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0094] Example 3

[0095] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0096] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0097] 37.12 kg tetraethyl orthosilicate, 0.1 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.3 kg ammonia (20 wt%), and 5.2 kg potassium hydroxide (purity 85 wt%);

[0098] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0099] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0100] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0101] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0102] Example 4

[0103] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0104] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0105] 37.12 kg tetraethyl orthosilicate, 0.4 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 1.0 kg ammonia (20 wt%) and 5.2 kg potassium hydroxide (purity 85 wt%);

[0106] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0107] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0108] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0109] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0110] Example 5

[0111] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0112] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0113] 37.12 kg tetraethyl orthosilicate, 0.5 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 1.2 kg ammonia (20 wt%) and 5.2 kg potassium hydroxide (purity 85 wt%);

[0114] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0115] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0116] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0117] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0118] Example 6

[0119] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0120] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0121] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 75 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%), and 5.2 kg potassium hydroxide (purity 85 wt%);

[0122] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0123] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0124] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0125] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0126] Example 7

[0127] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0128] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0129] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 50 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%), and 5.2 kg potassium hydroxide (purity 85 wt%).

[0130] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0131] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0132] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0133] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0134] Example 8

[0135] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0136] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0137] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 125 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 33 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%), and 5.2 kg potassium hydroxide (purity 85 wt%);

[0138] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0139] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0140] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0141] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0142] Example 9

[0143] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0144] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0145] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%) and 4.7 kg potassium hydroxide (purity 85 wt%);

[0146] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0147] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0148] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0149] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0150] Example 10

[0151] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0152] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0153] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%), and 5.5 kg potassium hydroxide (purity 85 wt%);

[0154] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0155] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0156] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0157] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0158] Example 11

[0159] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0160] (1) Weigh the raw materials of the K2O·nSiO2-based pre-reaction spinning solution according to the following weights:

[0161] 37.12 kg tetraethyl orthosilicate, 0.3 kg nitric acid, 57.73 kg deionized water, 100 kg polyethanol aqueous solution (solid content: 5 wt%; molecular weight: 80,000-100,000; degree of hydrolysis: 85%-90%), 3 kg ethanol, 1.5 kg reactive emulsifier SE-10N, 0.8 kg ammonia (20 wt%) and 5.8 kg potassium hydroxide (purity 85 wt%);

[0162] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0163] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as that of the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1, except that the composition of the K2O·nSiO2-based pre-reaction spinning solution is different.

[0164] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0165] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0166] Example 12

[0167] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0168] (1) Weigh the raw materials of the same K2O·nSiO2-based pre-reaction spinning solution as in Example 1:

[0169] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0170] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1.

[0171] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0172] The composite windshield for high-speed locomotives in this embodiment is manufactured using the aforementioned PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film through the following steps:

[0173] (1) Prepare 4 pieces of 5mm thick ultra-strong chemically tempered glass;

[0174] (2) A first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is laid on a first layer of ultra-strong chemically tempered glass, so that the input wire and the output wire protrude from the windshield. A second layer of ultra-strong chemically tempered glass is laid on the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film, followed by several layers of uniformly thick second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. Then, a third layer of ultra-strong chemically tempered glass is laid on the second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film, followed by several layers of uniformly thick third layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. Finally, a third layer of ultra-strong chemically tempered glass is laid on the third layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. A fourth layer of ultra-strong chemically tempered glass is laid on an O2-based nanofiber / PVB interpenetrating network film. Then, an anti-splash layer is laid on top of the fourth layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. Finally, the stacked ultra-strong chemically tempered glass layer, PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film, and anti-splash layer are placed together in a vacuum bag and a vacuum is drawn. The vacuum bag is then placed in an autoclave and reacted at 110–115°C and 1–1.5 MPa for 0.5–1.5 hours. The vacuum bag is then removed to obtain a composite windshield for high-speed locomotives.

[0175] Example 13

[0176] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0177] (1) Weigh the raw materials of the same K2O·nSiO2-based pre-reaction spinning solution as in Example 1:

[0178] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0179] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1.

[0180] The preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in this embodiment is the same as the preparation method of the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached electrothermal component in Example 1.

[0181] The composite windshield for high-speed locomotives in this embodiment is manufactured using the aforementioned PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film through the following steps:

[0182] (1) Prepare 5 pieces of 5mm thick ultra-strong chemically tempered glass;

[0183] (2) A first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is laid on a first layer of ultra-strong chemically tempered glass, so that the input wire and the output wire protrude from the windshield. A second layer of ultra-strong chemically tempered glass is laid on the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film, followed by several layers of uniformly thick second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. Then, a third layer of ultra-strong chemically tempered glass is laid on the second layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film, followed by several layers of uniformly thick third layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. Finally, a third layer of ultra-strong chemically tempered glass is laid on the third layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. A fourth layer of ultra-strong chemically tempered glass is laid on an O2-based nanofiber / PVB interpenetrating network film. Then, several layers of uniformly thick fourth-layer PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film are laid on top. A fifth layer of ultra-strong chemically tempered glass is then laid on the fourth-layer PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. An anti-splash layer is then laid on top of the fifth PVB film layer. Finally, the stacked ultra-strong chemically tempered glass layer, PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film, and anti-splash layer are placed together in a vacuum bag and evacuated. The vacuum bag is then placed in an autoclave and reacted at 110–115°C and 1–1.5 MPa for 0.5–1.5 hours. The vacuum bag is then removed to obtain a composite windshield for high-speed locomotives.

[0184] Example 14

[0185] The K2O·nSiO2-based pre-reactive spinning solution in this embodiment was prepared by the following steps:

[0186] (1) Weigh the raw materials of the same K2O·nSiO2-based pre-reaction spinning solution as in Example 1:

[0187] (2) Prepare a K2O·nSiO2-based pre-reaction spinning solution using the same preparation method as in Example 1:

[0188] The preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in this embodiment is the same as the preparation method of the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film in Example 1.

[0189] In this embodiment, the first layer of PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached heating element is prepared by the following steps using the aforementioned PVB / high-modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film for the attached heating element:

[0190] See Figure 4 The system includes two sets of electric heating components 8 connected in parallel. In this embodiment, the two sets of electric heating components 8 for the composite windshield of the high-speed locomotive are located at different positions on the composite windshield, with the vertical center line of the composite windshield as the boundary. The first set of electric heating components 8 is located on the left half of the composite windshield, and the second set of electric heating components 8 is located on the right half. The input wire 831 of the first set of electric heating components 8 is connected to the output terminal of the first temperature controller, and its output wire 832 is connected to the input terminal of the same temperature controller. This electric heating component is controlled by the first temperature controller. The input wire 831 of the second set of electric heating components 8 is connected to the output terminal of the second temperature controller, and its output wire 832 is connected to the input terminal of the same temperature controller. This electric heating component is also controlled by the second temperature controller. In other embodiments, the number of heating elements 8 can be two or more. The heating elements can be set according to the area size of the composite windshield glass for high-speed locomotives and specific usage needs. The number, model, and layout of each component in each heating element can be the same or different. Since the area of ​​the composite windshield glass for high-speed locomotives is large and the operating range of high-speed trains is wide, snow and frost may accumulate in some areas of the train's windshield. By setting heating elements in different areas on the composite windshield glass for high-speed locomotives and controlling the heating elements in each area separately, the snow and frost on the windshield can be removed more effectively, making it more energy-efficient and environmentally friendly.

[0191] In this embodiment, the diameter of the heating wire 81 is 0.1-0.2 mm. If the diameter of the heating wire 81 is too thin, it is easy to break during the film laying stage, which will cause the heating component to malfunction. If the diameter of the heating wire 81 is too thick, it will occupy more film space, causing the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film 3 to be unable to firmly bond the first ultra-strong chemical tempered glass layer 2 and the second ultra-strong chemical tempered glass layer 4 with anti-reflective layer 1. When the diameter of the heating wire 81 is 0.1-0.2 mm, it can ensure long-term effective operation and ensure that the PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film has good adhesion. The heating wire 81 is preferably a tungsten heating wire. Because the heating wires dispersed in PVB / high-modulus K2O·nSiO2-based nanofibers / PVB interpenetrating network film are inconvenient to maintain, and the service life of composite windshields for high-speed locomotives is generally more than 10 years, and their operating environment is mostly harsh natural environment, the heating wires need to have sufficient stability and corrosion resistance. Tungsten heating wires have good plasticity, their structure is not easily changed when used at high temperatures, and they have strong corrosion resistance, so they are particularly suitable for composite windshields for high-speed locomotives.

[0192] The lamination method for the composite windshield glass for high-speed locomotives in this embodiment is the same as the lamination method for the composite windshield glass for high-speed locomotives in Embodiment 1.

[0193] Comparative Example 1

[0194] The preparation method of the composite windshield glass for high-speed locomotives in this comparative example is the same as that in Example 1. The difference lies in the composition of the adhesive layer material. In this comparative example, the adhesive layer contains only PVB film.

[0195] Comparative Example 2

[0196] The adhesive layer material in this comparative example was prepared through the following steps:

[0197] A 0.38 mm PVB film was immersed in a K2O·nSiO2-based pre-reaction solution with a modulus of 5. After curing, an immersion-type PVB / K2O·nSiO2 film was obtained.

[0198] The preparation method of the composite windshield glass for high-speed locomotives in this comparative example is the same as that of the composite windshield glass for high-speed locomotives in Example 1, the difference being the preparation method of the adhesive layer material.

[0199] Fire resistance tests were conducted on the composite windshields for high-speed locomotives prepared using the film materials provided in Examples 1-13 and Comparative Examples 1-2, according to GB / T12513-2006, Fire Resistance Test Method for Glass Components. The fire resistance time of the composite windshields for high-speed locomotives was obtained. Four parallel samples were used in the experiment, and the average value was taken as the experimental result. The transmittance of each composite windshield for high-speed locomotives was obtained by glass transmittance testing, and the appearance quality of each composite windshield for high-speed locomotives was obtained by visual observation. The performance parameters of the composite windshields for high-speed locomotives prepared in the embodiments and comparative examples of this invention are shown in Table 1.

[0200] Table 1 Performance parameters of composite windshield glass for high-speed locomotives

[0201]

[0202] *ΔT=(T t0 -T tn ) / T t0

[0203] T tn It is the transmittance after 3000 hours of ultraviolet irradiation, T t0 It is the initial transmittance.

[0204] As shown in Table 1, the composite windshield for high-speed locomotives of this invention exhibits excellent fire resistance, while the composite windshield for high-speed locomotives prepared in the comparative example fails within 20 minutes. The fire resistance of the composite windshield for high-speed locomotives of this invention is 1.5-2.5 times higher, and its transmittance and UV irradiation resistance are also significantly higher than the fire-resistant glass of the comparative example. This demonstrates that the high-modulus K₂O·nSiO₂-based nanofibers do not affect the low-temperature resistance of the PVB film, allowing for use in low-temperature (-55℃) and outdoor environments. The composite windshield for high-speed locomotives prepared in this embodiment of the invention has the advantages of being free of microbubbles, having high transmittance, long fire resistance time, and resistance to low temperatures and UV irradiation.

[0205] By comparing Examples 1-13 with Comparative Examples 1-2, it can be seen that when using the same film material, as the number of glass layers gradually decreases, the transmittance becomes better and better, the low-temperature resistance remains unchanged, and the fire resistance time gradually decreases.

[0206] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0207] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A composite front windshield for high speed vehicles, comprising a splash-proof layer, an electric heating assembly, a plurality of super-strong chemical glass layers and a bonding layer, characterized in that, At least one of the adhesive layers is a PVB / high-modulus K2O nSiO2-based nanometer soft fiber / PVB interpenetrating network film, the PVB / high-modulus K2O nSiO2-based nanometer soft fiber / PVB interpenetrating network film comprising an interpenetrating network structure made of PVB and high-modulus K2O nSiO2-based nanometer soft fiber, the high-modulus K2O nSiO2-based nanometer soft fiber being K2O nSiO2-based nanometer soft fiber with a diameter of 200-600 nm and a modulus of 4.0-4.5; wherein the PVB / high-modulus K2O nSiO2-based nanometer soft fiber / PVB interpenetrating network film is prepared by the following steps: Step 100) preparing a K2O nSiO2-based pre-reaction spinning solution, the specific steps being as follows: Step 101) mixing tetraethyl orthosilicate, nitric acid and deionized water in a weight ratio of 18-75:0.1-0.5:30-120, stirring at room temperature for at least 60 minutes to allow the mixture to hydrolyze fully, and then stirring for another 60 minutes after the formation of monomodal narrow-distribution silica sol with a particle size of 70-100 nm to prepare a first mixed solution; Step 102) adding polyvinyl alcohol aqueous solution, ethanol and reactive emulsifier SE-10N to the first mixed solution in a weight ratio of 50-200:2-4:1-2, stirring at room temperature for at least 60 minutes to prepare a second mixed solution with a viscosity maintained in the range of 20-80 mPa·s; wherein the solid content of the polyvinyl alcohol aqueous solution is 5 wt%, the molecular weight of the polyvinyl alcohol used to prepare the polyvinyl alcohol aqueous solution is 80000-100000, and the degree of hydrolysis of the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 85%-90%; Step 103) slowly adding 0.4-1.2 parts of ammonia water to the second mixed solution, stirring at room temperature for at least 60 minutes to prepare a third mixed solution with a pH value maintained between 6 and 7; wherein the mass concentration of the ammonia water is 20 wt%; Step 104) adding 4-8 parts of potassium hydroxide to the third mixed solution step by step, ensuring that the solution system temperature is below 25°C, and then vacuum defoaming for 60 minutes to prepare a K2O nSiO2-based pre-reaction spinning solution with a viscosity maintained in the range of 40-210 mPa·s; wherein the purity of the potassium hydroxide is 85 wt%; Step 200) preparing high-modulus K2O nSiO2-based nanometer soft fiber, the specific operation being as follows: using the K2O nSiO2-based pre-reaction spinning solution prepared in step 100) to prepare low-modulus K2O nSiO2-based nanometer fiber; Step 300) using PVB film and low-modulus K2O nSiO2-based nanometer fiber prepared in step S200) to prepare PVB / high-modulus K2O nSiO2-based nanometer soft fiber / PVB interpenetrating network film, the specific operation being as follows: Step 301) place the low modulus K2O·nSiO2-based nanofiber membrane made of low modulus K2O·nSiO2-based nanofiber between two PVB films to form a PVB / low modulus K2O·nSiO2-based nanofiber membrane / PVB composite structure, and then set a separation film on both sides of the PVB / low modulus K2O·nSiO2-based nanofiber membrane / PVB composite structure to separate the PVB film from the glass; Step 302) place the PVB / low modulus K2O·nSiO2-based nanofiber membrane / PVB composite structure and the separation film between two tempered glasses to form a pressing assembly, and then heat press the pressing assembly to obtain a PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film.

2. The composite front windshield for high speed vehicles as set forth in claim 1, wherein In step 302), the pressing assembly is placed in a continuous roller press for heat pressing, wherein in the first roller heat pressing, the roller pressure is 0.3±0.1 MPa, the roller temperature is 40±5 ℃, and the roller spacing is 88%-92% of the thickness of the pressing assembly; in the second roller heat pressing, the roller pressure is 0.5±0.1 MPa, the roller temperature is 70±5 ℃, and the roller spacing is 88%-92% of the thickness of the pressing assembly after the first pressing.

3. The composite front windshield for high speed railcars according to claim 1, wherein The thickness of the PVB film is 0.3-1.5 mm.

4. The composite front windshield for high speed railcars according to claim 1, wherein The separation film is a polyimide film.

5. The composite front windshield for high speed vehicles as set forth in claim 1, wherein The electric heating assembly comprises an electric heating wire, an input bus bar, an output bus bar, an input lead wire, and an output lead wire. The output end of the input lead wire is in electrical conductive connection with the input end of the input bus bar. The output end of the input bus bar is in electrical conductive connection with the input end of the electric heating wire. The output end of the electric heating wire is in electrical conductive connection with the input end of the output bus bar. The output end of the output bus bar is in electrical conductive connection with the input end of the output lead wire. The input end of the input lead wire protrudes out of the super-strong chemically tempered glass layer and the first PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. The output end of the output lead wire protrudes out of the super-strong chemically tempered glass layer and the first PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film. The first PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film is arranged in the order of PVB / high modulus K2O·nSiO2-based nanofiber / PVB interpenetrating network film from the outside to the inside.

6. The composite front windshield for high speed railcars according to claim 1, wherein The surface stress of the super-strong chemically tempered glass layer is 400-900 MPa, the stress layer depth is 20-50 μm, and the thickness is 3-10 mm.

7. The composite front windshield for high speed railcars according to claim 1, wherein The K2O.nSiO2-based pre-reaction spinning solution is composed of 25-55 parts by weight of ethyl orthosilicate, 0.2-0.4 parts by weight of nitric acid, 45-70 parts by weight of deionized water, 75-133 parts by weight of polyvinyl alcohol aqueous solution, 2.5-3.5 parts by weight of ethanol, 1.3-1.7 parts by weight of reactive emulsifier SE-10N, 0.6-1.0 parts by weight of ammonia water and 4.5-6.5 parts by weight of potassium hydroxide.

8. The composite front windshield for high speed railcars according to claim 1, wherein The K2O.nSiO2-based pre-reaction spinning solution is composed of 37.12 parts by weight of ethyl orthosilicate, 0.3 parts by weight of nitric acid, 57.73 parts by weight of deionized water, 100 parts by weight of polyvinyl alcohol aqueous solution, 2 parts by weight of ethanol, 1 part by weight of reactive emulsifier SE-10N, 0.8 parts by weight of ammonia water and 4.7 parts by weight of potassium hydroxide.

9. The method of claim 1, wherein the composite front windshield glass for high speed vehicles is prepared by the steps of: The method comprises the following steps: ​ Step 401) laying the first layer of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film on the first layer of super-strong chemical toughened glass layer, so that the input and output leads project out of the first layer of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film and the super-strong chemical toughened glass layer; Step 402) laying the second layer of super-strong chemical toughened glass layer on the first layer of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film; Step 403) laying a plurality of second layers of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network films with uniform thickness on the second layer of super-strong chemical toughened glass layer; Step 404) laying the third layer of super-strong chemical toughened glass layer on the second layer of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film; Step 405) laying the third layer of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film on the third layer of super-strong chemical toughened glass layer; Step 406) laying the anti-splashing layer on the third layer of PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film; Step 407) placing the laminated super-strong chemical toughened glass layer, PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film and anti-splashing layer together in a vacuum bag and vacuumizing; Step 407) placing the vacuum bag containing the laminated super-strong chemical toughened glass layer, PVB / high-modulus K2O.nSiO2-based nanometer soft fiber / PVB interpenetrating network film and anti-splashing layer in an autoclave and reacting at 110-115℃ and 1-1.5Mpa for 0.5-1.5h, and then removing the vacuum bag to obtain the composite front windshield glass for high-speed vehicles.

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